1. Field of the Invention
The present invention relates to an acid generator containing an aromatic ring, and more particularly, the invention relates to an acid generator containing an aromatic ring, which is included in a chemically amplified resist composition used in semiconductor processes.
2. Description of the Related Art
A chemically amplified resist composition used in the semiconductor fine processing utilizing lithography contains an acid generator, and as the technologies supporting the semiconductor fine processing continue to develop, a demand for resists with higher resolution still exists.
Therefore, in order to produce a resist having an increased resolution and desired properties, a large number of different acid generators have been developed, and in order to improve the diffusion rate of acid and transparency, which are some of the properties associated with high resolution, numerous modifications and experiments in the design of the cation moiety of the salts used as acid generators, have been carried out.
However, in the recent studies of resist compositions, the development of photoacid generators focused on the cation moiety is beginning to face limits in the improvement of resist properties, and there has occurred a problem of reducing effluence into water, which is required as water is used in the immersion ArF processes.
Therefore, based on a number of experimental data and articles reporting that the anion moiety can exert greater influence than the cation moiety on the physical and chemical properties which substantially improve the fluidity of acid and the properties of the resist composition, new inventions associated with the anion moiety of acid generators have recently been achieved. These new inventions are focused on the invention of a photoacid generator which reduces the diffusion rate of acid, and can control the transmissibility of ArF radiation at 193 nm (for example, Korean Patent Application Nos. 10-2006-0104718, 10-2006-0133676, 10-2005-0107599, 10-2006-0114104 and 10-2008-0023406).